You'll have to add to this more to get it to look pretty or to fit your data. However code below shows examples of what you're trying to accomplish. I don't know about labeling % of BFS to be in the middle. I know the File Exchange has some good Axes labeling, or you can insert the text knowing the total length of all the subplots.
x=[0 30 50 80];
y=rand(4);
h1=subplot(1,2,1);
plot(x,y,'-.');
box off
xlim([-10 90])
set(h1,'Xtick',x)
h1_pos = get(h1,'Position');
y2 = 10*y.^2;
h2=subplot(1,2,2);
plot(x,10*y,'-.');
y2lim = get(h2,'YLim');
set(h1,'Ylim',[0 y2lim(2)])
box off
set(h2,'Ycolor',[1 1 1])
xlim([-10 90])
set(h2,'Xtick',x)
h2_pos=get(h2,'Position');
set(h2,'Position',[h1_pos(1)+h1_pos(3) h2_pos(2:end)])
set(h2,'YTickLabel','')
Best Answer